Lathe attachment for elliptical and circular turning



Dec. 4, 1962 J. ESTEPHANIO LATHE ATTACHMENT FOR ELLIPTICAL AND CIRCULAR TURNING Filed Aug. 16, 1955 3 Sheets-Sheet l Dec. 4, 1962 J. ESTEPHANIO 3,066,560

ICAL AND CIRCULAR TURNING FIG. 4.

LATHE ATTACHMENT FOR ELLIPT 3 Sheets-Sheet 2 Filed Aug. 16, 1955 ,a cum: MEMBER E PIN 2 J. ESTEPHANIO 3,

LATHE ATTACHMENT FOR ELLIPTICAL AND CIRCULAR TURNING Filed Aug. 16. 1955 3 Sheets-Sheet 3 United States Patent Ofifice Bfihbjhil Patented Dec. 4, 19%2 The present invention relates to automatic lathes, and more particularly to the construction and operation of the lathe head-stock.

In automatic lathes of known construction, it has been common practice to provide either for rotation of the workpiece (i.e., the workpiece being machined), with the tool being held in fixed position; or, alternatively, for rotation of the tool, with the workpiece being held in fixed position. in either case, however, it has been possible to obtain only circular movement of the workpiece.

It is therefore a principal object of the present invention to provide means ensuring rotation of the workpiece being machined in a predetermined non-cylindrical path, preferably in an elliptical or oval path, while the automatic lathe head stock is in operation.

It is a further object of the present invention to provide means facilitating the production of workpieces with elliptical or oval-shaped surfaces.

Still another object of the present invention is to provide means affording rapid and simplified adjustment of an automatic lathe head stock for either circular or elliptical rotation of the workpiece being machined.

These and "other objects of the invention will become further apparent from the following detailed description, reference being made to the accompanying drawings showing a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a perspective view, as seen from the rear end, of a head stock of an automatic lathe made in accordance with the invention, supporting a workpiece.

FIG. 2 is a perspective view of the support plates for the headstock of FIG. 1;

FIG. 3 is another perspective view, as seen from the front end, of the headstock of FIG. 1, shown in position on the rails of a lathe bed;

FIG. 4 is a transverse sectional view of the headstock of FIG. 1;

FIG. 5 is a perspective view of a slide piece with guide pins according to the invention;

FIG. 6 is a perspective view of the headstock, with the guide member and slide piece in an eccentric position;

FIG. 6a is a diagrammatic showing of the elliptical path of the workholding chuck;

FIG. 7 is a transverse sectional view of the headstock of FIG. 6;

FIG. 8 is a view similar to that of FIG. 6, but showing the slide piece in central position;

FIG. 9 is a vertical sectional view of the headstock of FIG. 8;

FIG. 10 is a longitudinal sectional view of the slotted plate member embodying the invention;

FIG. 11 is an exploded view in section, showing the plate member, slide piece and locking plates embodying the invention;

FIG. 12 is a longitudinal sectional view of the assembled plate member, slide piece and locking plates constructed according to the invention;

FIG. 13 is a perspective view of the guide member mounted on the slide plate therefor and having a spindle passing therethrough; and

FIG. 14 is a front plan view of the guide member of FIG. 13.

Referring now more specifically to the drawings, there is shown the headstock 2d of a lathe (not shown) in accordance with the invention. The headstock spindle 1 is connected for rotation to a conventional power drive (not shown). A plate member 2 is fixedly mounted at its center on the outer end in of spindle 1 by means of a threaded connection (not shown), and extends transversely of the spindle. Plate member 2 is provided with absubstantially rectangular channel 2a on its front face Fitted within the channel 2a of plate member 2 is a slide piece 4, having a generally trapezoidal base portion 40, and a rectangular extension portion ad which projects outwardly from the channel 2a.

Two beveled locking plates 3 (FIG. 11) also fit within said channel 2a, one above and one below the slide piece 4, and are bolted to the plate 2. These locking plates 3 retain the slide piece 4 within the channel, while permitting transverse sliding movement thereof.

The rectangular portion 4d of slide piece 4 carries on its outer face a threaded post 5 (FIG. 5) adapted to support an object or workpiece for rotation by the headstock. Slide piece 4 also carries at each end thereof an inwardly extending guide pin 6. Each of the pins 6 passes through an elongated slot x provided adjacent each side edge and along the horizontal center line of the plate 2 (FIG. 10). Two conical guide heads 7 and 8 are1 rrliounted on each end of pins 6 as seen in FIGS. 5 an The two cones 7, 8 are positioned along separate axes, and the outer cone 8 is smaller than, and displaced with respect to the inner cone 7, as clearly apparent from FIG. 7.

The workpiece to be machined, supported by the post 5, is indicated at 9. These means for the support of the workpiece may be of conventional type, and therefore need not be further described.

A guide member 14 (FIG. 14) is positioned adjacent the rear face of plate 2, and is provided with a bore 14a through which the spindle 1 passes. The front face of member 14 is provided with a frusto-conical projection 14b having an axis concentric with the spindle 1. Beneath this projection 14b and spaced therefrom, the member 14 is further formed with a U-shaped projection 14c providing an upper beveled bearing surface 14d. The two projecting portions 14b, 140, thus, provide therebetween a groove Me generally trapezoidal in cross-section, this groove being adapted to slidingly receive the heads 7 and 8 on the pins 6. The groove 14:; extends through an arc of at least but less than (FIGS. 13 and 14).

The member 14 is mounted for longitudinal movement along a lathe bed 10 having parallel support rails (FIG. 3), and also for transverse movement thereof. For such mounting, a support plate 13 (FIG. 2) is provided. Plate 13 is formed on its upper surface with two parallel rails y extending transversely of the lathe bed. The rails y are each bevelled along their side faces to provide a central slideway of trapezoidal cross-section, and an angular slideway along each side thereof.

The plate 13 is adapted to slide along the rails of the lathe bed 10. A bottom retainer plate 11 cooperates with the plate 13, to maintain the latter in position on the rails of the lathe bed. The plate 11 carries an upwardly extending bolt 12. The plate 13 has a central bore for passage of the bolt 12, and a nut is provided for said bolt. Additional bolts 16 are also provided for attachment of member 14 to plate 13.

The bottom of the member 14 is formed with two parallel transversely extending grooves 17 corresponding in shape to the rails y. Member 14 is thereby adapted for sliding engagement of the rails y, as shown at 15.

In assembling and operating the headstock, the plates 11 and 13 are first positioned at the desired point along the lathe bed 10. The member 14 is then mounted on the plate 13. The plate 2 may then be screwed into position on the end of spindle 1, and the slide piece 4 and locking plates 3 fitted into place. As has been above indicated, the conical heads 7 and 8 on pin 6 are slidingly received in the trapezoidal groove 145 on the front face of guide member 14. As clearly shown in FIGS. 4 and 7, the heads are so positioned that one head 7 rides along one side wall of the groove 142, while the other head 8 rides along the other side wall of said groove. This arrangement serves to prevent breakage of the heads when engaged within the groove Me.

With the bolts 12 and 16 loosened (FIGS. 1, 2), the member 14 may be transversely shifted along the plate 13. A corresponding shift of the slide piece 4 will take place. The bolts may then be tightened. If the member 14 and slide piece 4 are located concentrically with respect to spindle 1, as shown in FIGS. 4 and 8, rotational operation of the spindle 1 will result in circular motion of the workpiece supported at 9 for machining. If, however, the member 14 and slide piece 4 are shifted into an eccentric position, such as, for example, that shown in FIGS. 6 and 7, operation of the spindle will result in transverse displacement of the slide piece 4 with each turn of the spindle. As a consequence, elliptical motion will be produced for the workpiece being machined, as may be readily realized.

It is to be recognized that the conical guide heads 7 and 8 are each assembled to one axle with two sections, one being displaced to the other in order that the lateral support of the ends is in one side of the groove x by one of the guide heads and in the other side of the groove Me by another of the guide heads preventing the possibility of breaking in the guide groove. Further, the eccentric movement of the workpiece in its elliptical rota tion while supported by the workholder slide piece 4 will correspond to the displacement of the guide pins 6 in the grooves 14c.

Various changes and modifications may be made without departing from the spirit and scope of the present invention and it is intended that such obvious changes and modifications be embraced by the annexed claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent, is:

1. In an automatic lathe, a mechanical movement between a rotatable spindle and a workholder slide piece; comprising a substantially vertical plate member having a front face and rear face and fixedly mounted on said spindle, said front face of said plate member being provided with a channel and with slot means passing through said plate member within the confines of said channel, said workholder slide piece being movably mounted within said channel and adapted to support a'workpiece to be machined, two spaced guide pins fixed to and extending from said slide piece through said slot means, a guide member provided with a vertical face and having a bore therethrough for passage of said spindle, said guide mem her face being provided with a groove extending along a circular arc concentric with said bore and being posi tioned parallel to and adjacent said rear face of said plate member, and head elements carried by said guide pins and slidably extending in said groove, whereby, when said guide member and slide piece are positioned eccentrically with respect to said spindle and said spindle is rotated about its axis, said slide piece will perform an elliptical rotation which will be imparted to the workpiece.

2. in an automatic lathe, a mechanical movement between a rotatable spindle and a workholder slide piece; comprising a vertical plate member having a front face and a rear face and being fixedly mounted on said spindle, said front face of said plate member being provided with a channel and with slot means passing through said plate member within the confines of said channel, said workholder slide piece being movably mounted within said channel and adapted to support a workpiece to be machined, two spaced guide pins extending from said slide piece through said slot means, a guide member providing a vertical face and having a bore therethrough for passage of said spindle, said guide member face being provided with a frustro-conical projection concentric with said bore and a U-shaped projection having a bevelled innor surface spaced from said frustro-conical projection, said frustro-conical and U-shaped projections providing therebetween a groove trapezoidal in cross-section and extending along a circular arc concentric with said bore, said guide member face being positioned parallel to and adjacent said rear face of said plate member, and head elements carried by said guide pins and slidably extending in said groove, whereby, when said guide member and slide piece are positioned eccentrically with respect to said spindle and said spindle is rotated about its axis elliptical rotation will be imparted to the workpiece, while the latter is supported by said workholder slide piece.

3. In an automatic lathe, a mechanical movement between a rotatable spindle and a workholder slide piece; comprising a vertical plate member having a front face and a rear face and being fixedly mounted on said spindle, said front face of said plate member being provided with a channel and with slot means passing through said plate member within the confines of said channel, said workholder slide piece being movably mounted within said channel and adapted to support a workpiece to be machined, two spaced guide pins extending from said slide piece through said slot means, a guide member providing a vertical face and having a bore therethrough-for passage of said spindle, said guide member face being provided with two walls angularly directed to each other and defining a groove extending along a circular are concentric with said bore and being positioned parallel to and adjacent said rear face of said plate member, and two conical head elements carried by each of said guide pins and slidably extending in said groove, said two head elements respectively carried by each of said pins differing in size and being axially displaced with respect to one another, one of said elements being siidable along one of said walls, and the other of said elements being slidable along the other of said walls, whereby, when said guide member and slide piece are positioned eccentrically with respect to said spindle and said spindle is rotated about its axis, elliptical rotation will be imparted to the workpiece, while the latter is supported by said work holder slide piece. i i V References (lite-d in the file of this patent UNITED STATES PATENTS 2,004,283 Hurt June 11, 1935 2,394,741 Beard Feb. 12, 1946 2,453,744 Chambliss Nov. 16, 1948 2,775,128 Young Dec. 25, 1956 FOREIGN PATENTS 450,875 ltaly Aug. 13, 1949 

